BMW E36 Aluminum Coolant Expansion Tank R&D, Part 2: Initial 3D Model and Prototype
Interested in picking up this aluminum E36 expansion tank? Check out our product page linked below!
Time to break open the stock tank and see what lies within. If you follow some of our other development projects, you would know that we recently split an E46 3-series expansion tank and found quite a complex system including both internal and external features. Although this added some complexity and difficulty to the project, it seemed like our engineers enjoyed the challenge.
Stock Expansion Tank Internals
First, before we slice this guy in half, a look inside the tank from the cap.
We can see from this shot that the tank does indeed feature a unique internal chamber. A tube appears to run the full length of the tank. Let's get to the band saw so we can split this component for evaluation.
The internal tube is easily removed and is shown below. It seals with O-rings on both the upper and lower portions of the tank.
This tube connects between the fill neck and the lower portion of the tank. It works as an internal expansion chamber to relieve pressure and properly bleed air from the coolant.
We would need to incorporate this feature into our design to ensure stock-like functionality.
Instead of jumping into fabrication of a prototype from aluminum, we decided to take a slightly different approach for this project. We began by creating our design in Solidworks, after which we would use our 3D printer to create a prototype for checking fitment. Check out some of the shots from the modeling process.
And here's a shot of the two ports on the base of the tank.
Check out the nice cutaway below showing the internal tube that will function in a similar fashion to the stock plastic unit.
Our final renderings show the Mishimoto expansion tank cap and bleeder/dipstick.
With a solid model complete in 3D, we could now turn this digital component into something we could handle and install to verify fitment. We fired up our new 3D printer and knocked out a prototype.
The fittings and ports were printed separately and attached after the print was complete. Check out a few shots of our assembled prototype.
Check out a couple shots of our tank next to the stock unit.
After collecting a few dimensional notes regarding our prototype, we brought a test vehicle into the shop and fit our component into place. Below is a before and after shot comparing the stock tank to our prototype unit mocked into position.
We then installed this expansion tank on our prototype electric fan mount. This is another project we have been working on for the E36.
Check back with us for a look at our final prototype! We will be installing this unit on our test vehicle to ensure both fitment and proper functionality.